Gymnosperms and angiosperms Flashcards
Advantages of seeds:
– Embryo can remain dormant
– Seeds can aid the dispersal of the embryos
– Additional protection for embryo
* (more than the archegonium)
unicellular oogonium—- multicellular archegonium—- seed
* E.g. protection from dessication
– Provides nutrition for developing embryo
* Source of “food” varies
A. Phylum Pinophyta
conifers ex
*Pines
*Spruces
*Firs
*Cedars
*Hemlock
*Larch
*Dawn redwood
*Giant sequoia
B. Phylum Cycadophyta
– Cycads
– Still have motile sperm
– E.g. Zamia
C. Phylum Ginkgophyta
– Ginkgo
– Ginkgo means silver apricot in Chinese
– Fleshy covering over the seeds
– Still have motile sperm
C. Phylum Gnetophyta
ephedra (joint fir)
gentum
welwitschia
– Ephedra (“Joint fir”)
“Mormon tea” from Ephedra spp. found in the plains & desert
southwest was used to treat STD’s.
* Ephedrine = drug from Asian Ephedra spp. such as E. sinica
(not in North American species)
– 2004 FDA ban on dietary products with ephedrine
– Can cause stroke and sudden death
Gnetu
found in tropics
Welwitschia
-each plant makes two leaves
-SW african desert
-CAM plant
memorize pin life cycle but heres a few things you need to knwo
its heterospory
has megapspores and microspores
no antheridia
first time we see seeds
memorize pine ovuel
fruits are
enlarged ovaries containing seeds fruits
-protect seeds
-aid in dispersal of seeds
controlled
fruit develeopment
Developing fruits inedible Become fleshy and edible—— Ethylene
ripens many fruits—–(seeds now ready to be dispersed)
angiosperms life cycle need to know
First time we see:
*fruits,
*flowers,
*3N endosperm
*No longer any
multicellular
gametangia
Male
gametophyte
= pollen grain
= 3 nuclei
Female gametophyte
reduced to 8 nuclei,
NO ARCHEGONIA
double fertilization
Megasporocyte is surrounded by nucellus
(megasporangium) in the ovule (pre-seed)
